Review my site: CloudSafe.com
It´s a place to store any critical data you would like to be securely encrypted in the cloud. Just setup a virtual safe and use the web frontend or WebDAV to upload your files. Then you can give selective access to any other user. Or you could use and distribute access codes for the safes.
From a technical perspective: We focused to implement a secure asmyetric cryptographic archtitecture - all content is encrypted via AES-256 and user access administration is done via public/private key encryption. So basically we tried to implement some of the key security elements of GPG/PGP within a cloud service.
The free account comes with three safes and 1GB of free space. Now we would love to get some user feedback: Just use our contact form on the site or drop us a quick note at support@cloudsafe.com.